Bugle calls were utilized on posts to communicate to soldiers throughout the day about drills, assemblies, roll calls, meals, and bedtime. A large megaphone helped magnify the sound to be heard throughout the post.
A typical day was organized as follows, with commands for each activity being communicated by a bugle call:
- Reveille or the wake up call sounded at daybreak.
- Assembly or roll call sounded a few minutes later.
- For mounted troops, stable call came immediately after reveille, forty minutes before noon and again immediately after retreat at sunset. The men cleaned the stables and fed and watered the horses. Infantry jokingly referred to the dragoons as "nursemaids".
- Sick call also came before breakfast at 7:10, and any who were ailing were sent to the post surgeon for examination and treatment, if needed.
- Mess call for breakfast sounded at 7:30 am. Lunch was at noon and evening mess was scheduled at the company level and was governed by the completion of routine work or fatigue duties.
- Fatigue call was sounded after breakfast, and the men were detailed from each company for such jobs as working on a construction site, cutting timber, hauling wood, working at the sawmill, cleaning the post, loading and unloading supplies, building a road, tending the post gardens, and numerous other duties.
- Those assigned guard duty, which was done on a rotating basis, were not assigned to work details. The changing of the guard, or guard mounting, was held mid morning and accompanied by another bugle call. Guards were on duty for twenty-four hours and were usually divided into three reliefs. Each relief stood guard for two hours and was off for four hours on a rotating basis.
- Drill instruction, which occurred only one or two days a week, was called at 10:00 am and occasionally after lunch at 1:00, after which the soldiers returned to fatigue duties.
- The daily retreat ceremony (lowering of the flag) occurred at sunset, was preceded by the fourth roll call of the day, and could include an evening dress parade.
- In the 1840s, the last bugle call of the day was tattoo, which required all soldiers to be at their quarters unless they were on special leave or guard duty. The fifth and final roll call was conducted immediately after the sounding of tattoo before the soldiers entered their quarters for the night.
Bugle call information provided by: https://www.nps.gov/fosc/learn/education/infantry8.htm